London Underground staff are out on strike. It is perhaps fitting, in the week when the Blitz began in the city 70 years ago, that most Londoners (Mayor Boris Johnson and media excepted) have not made an awful lot of fuss.

The Business Secretary, Vince Cable, suggests that the RMT’s Bob Crow, who is spearheading the Tube action, is an “embarrassment” to leaders of bigger unions. But could Cable have underestimated the strength of opposition within the movement – and the public – to the coalition’s economic plans?

This time last year, the union leaders we interviewed were anxiously anticipating the return of a Conservative government. Today, confronted by the Con-Lib coalition’s cuts, they tell us to expect a fight. Not all of them may put it as forcefully as Crow, but they appear united in their readiness to resist. The Labour leadership contenders pledge to work with trade unionists in order to win again. It will be interesting, therefore, to see which Miliband emerges as leader. David or the union-favoured Ed.